Method of making briquettes



R. T. BOV\(LING 1,990,632

METHOD MAKING BRIQUETTES Fild Dec. 25, 1952 2 Sheets-Sheet 1 AllorneyFeb. 12, 1935. R, T. BOWLING 1,990,632

METHOD OF MAKING BRIQUETTES FiledDec. 23, 1932 2 Sheets-Sheet 2 I HHHH0T IJODEIQI T. DQWIIHG By f W ltorney Patented Feb. 12, 1935 Lewiston,Idaho Application December 23, nizis fiai Nb. 48,604

orandpther similar products, which are finely in the core, and in theibriquette' made from the comminuted, andthis.comminuted material iscompressed toform a solid, cylindrical briquette which, possesses therequired solidity to insure durability for-commercial purposes, andwhich.

also possesses the necessary densityto insure slow disintegration whileburning." r Essentially, my improved process or method, involves atwo-stage compression'of the comminuted material, which I find to benecessary for the production of a briquette that fulfills the aboverequirements. Bytests, experiments and actual practice, 'I havesucceeded in overcoming diiiiculties, andl have solved problems, thatfor! merly stood in the way of themanufacture of a commerciallysuccessful briquette of this character.-

One of the diflicultiesencountered in the manufacture of the fuelbriquettes bycompression of. the comminuted material in a mold for thatpurpose, particularly white-pine, white-fir, red-fir, and othercone-bearing orconiferous woods, is the naturalresilience of thematerial, which heretofore has prevented the material from beingproperly compacted to insure durability. This difilculty I overcome bysubjecting the ma terial to a. continuous-compression: during thetimerequired for the manufacture of the briquette, which time. isapproximately twentysec ondsfora five pound briquette. i

Another problem which I havesolved by the employment of my two-stagecompression proc-' ess for the material involves the creation of heatcore, due to friction caused by the pressure to which the comminutedmaterial is subjected, and which forms the self-binder that isnecessaryto overcome the resilience of the material. I'he generated heatalso tendsto' cause expansion of the material, while the briquette is inprocess of -manufacture, and to overcome this tendency I subject thecore fromwhich the briquette is made, as wellas thebriquette itself, toa cooling step, which step. is initiated whilethe core and the briquetteare still held under compression, and

which cooling step iscontinued thereafter during a period of timesufiicient to cool the briquettep The mixture of sap, resin, pitch, andother natural moisture or organic gummy substances present in the.sawdust, is expressed from the particles of material, and this mixtureis employedasaninternalself-binder for the briquettex- 1 In carrying outmy two-stage compression process I employ the following steps, of finelyrialto a'first compression; severing a ribbon or continuous-laminationfrom this compressed mass; laying the ribbon in a spiralformation and simultaneously subjecting the spirally laid ribbon toasecondcompression to-form a core; heating the compressed mass and thecompressed core byinternal friction to express moisture and therebyprovide a self-binder; continuously subjecting the core topressureduring the formation of a briquette; fashioning the core into abriquette; cooling the briquette; employing the core in the step ofdelivering the completed briquette; and controlling the density of thebriquette.

In order that my improved process may readily be understood I'havedisclosed in .the accompanying drawings so much of a briquette-makingmachine as is necessary for the purpose, said machine forming thesubject matter of an application for patent Serial Number 648,603 filedby me under date of December 23, 1932.

Figure .1-' is a 'view partly in elevation and parity in sectionillustrating parts of the machine byv means of. which the steps of themethod are accomplished.

Figure 2 isa view partlyzin elevation and partly in section of thewater-cooled, rotary, moldcarrier, employed in the process ofmanufacturingthe briquettes.

Figure 3' is an enlarged vertical, longitudinal sectional detail viewshowing the process of forming the compressed mass, the core, and theresulting briquette.

In Figure 3 I show a housing 1 with a stationary mold 2 therein which isof frusto-conical form to provide a tapered feed chamber A, and aprocess or first compression chamber B inwhich the materialis firstcompressed into a compact, nonrotary mass.- The core C is cut from thismass in a continuous spiral ribbon and the spiral ribbon or continuouslamination, by a second com pression, is spirally laid to form the corethat eventuates in the briquette D. A movable mold M is employed toprovide part of the chamber in which the second compressiontakes place,and

this mold is one of an endless series of molds employed inthe formationand delivery of the rigidly secured 'on'the working end of the shaft,

and as best -seen'in Figure 3 a double-tapered spindle 9 iskeyed at 10in a socket atthe smaller end of the feed screw. The shaft 7 is tubularto accommodate a clamp rod 11, which has a threaded portion and a nut12, by means of which the spindle is drawn into and locked in itssocket.

The free end of the spindle is provided with a compression head 13 inthe form of a circular disk that is spaced a predetermined distance inadvance of the smaller end of the feed screw to form the firstcompression chamber in which the compressed mass of material is formedat B. The material in this chamber 13 is compressed by the action of thefeed screw, against the inner face of the compression head 13, and whileboth the feed-screw and the compression head revolve, intermittently, itwill be understood that there is no movement of the compressed mass ofmaterial adjacent to the compression head, at any time. The material islaid in a thick ribbon by the tapered screw and as the material isexpressed from the face of the screw it gradually loses its rotarymovement. Thereafter the mass in its first stage of compression, isintermittently and gradually pressed, longitudinally, toward the rearface of the head 13, its volume reduced, and

its density increased as the material nears the head. Thus, bythe'action of the tapered feed screw, in combination with thecompression head, the first stage of compression of the material isaccomplished, and a non-rotary, compact, mass of material is provided inthe chamber B.

In Figures 1 and 3 it will be seen that the compression head is providedwith a transversely arrangedrdiagonahrslot l i'sthat extends inwardlyfrom its outer periphery to the spindle, and thence beyond the spindleto the center of the head, gradually merging with the front face of thehead.

The rear face of the head is fashioned with a cutting edge 15 thatprojects slightly beyond the plane of the inner face of the head,and-this cutteris employed, as the head revolves, to slice or cut fromthe stationary, compressed, mass of material in the first compressionchamber B, a continuous ribbon, or spiral layer, which, while stillcompressed, and by action of the rotary compression head, is passedthrough the slot 14, from left to right in Figure 3.

The front face of the compression head 13 is a compression-face, and asindicated at 16 this iace is in the form of a spiral or annular camface.Thus, as the ribbon passes through and emerges from the slot 14, theribbon is laid" by the action of the cam-face or compression face of thehead, in spiral laminations to form the core C. This laying of theribbon in spiral formation to form the solid core C is the second stageof compression, and the pressure exerted under this second compressionis greater than .that of the first compression.

, screw forms and compresses a spiral layer of the material ofapproximately one-half inch thick, into the first compression chamber toform the compact mass; then the cutter 15 severs a spiral ribbon of thiscompressed mass of approximately five-sixteenths of an inch inthickness, and by the second stage of compression this ribbon is pressedinto spiral laminations' of approximately oneeighth of an inch inthickness, as indicated in Figure 3.

During the first stage of compression, the material, from a free state,is gradually compressed against the compression head and the walls ofthe compression chamber, and due to friction created by this compressionan internal heat lsgenerated. During the second stage this compressedmaterial is further compressed by means of the head 13 to a more soliddensity, and the internal heat thereby generated, due to friction,reaches a higher degree of temperature than that attained by the firstcompression.

The heat thus generated melts, dissolves, or thins the natural moisturecontent or natural organic gummy constituents of the wood so that thethinned moisture content under compression, is distributed over theentire area of the compressed material, including. the spirally formedlaminations that make up the core and briquette. This moisture contentforms a self binder which becomes most eflective when the briquette,still under compression, is cooled.

The second stage of compression of the core is accomplished against ayielding-resistance, which in this instance is produced by means of agradually-decreasing, hydraulic pressure, that is exerted against areclprocable head 1'? which is alined, axially, with the feed screw andthe compression head. The final compression is thus accomplished betweena rotary compression head and a yielding-resistance head, and theyielding resistance of the reciprocable head, may be varied, to vary thedensity or solidity of the resulting core C and the briquette D.

As best seen in Figure 1 the yielding-resistance head 1'1 is mounted onthe end of a reciprocable stem 18, which has a piston 19 reciprocatingin the oil cylinder 20 that is provided with an outlet pipe?! atone-wide of the piston and an oil inlet pipe 22 at the other, side ofthe piston. The head 17, at intervals, or intermittently, and bypositive mechanical action, is advanced toward the mold M, but stopsshort of the mold, then on its yielding-resistance or working stroke inthe opposite direction the head 17 moves to the right in Figure 1against the gradually-decreasing hydraulic pressure in the cylinder 20.r

The mold M, forming part of the second-stage compression chamber, is oneof an annular series of molds that are mounted in the circular, rotary,mold carrier 23, which'isprovided with a water jacket 24 enclosing theseries of molds. This jacket is supplied with water through the inletpipe 25 and the water flows from the jacket through outlet pipe 26, anaxial feed through the carrier shaft 27, being indicated for circulationof water from a suitable source.

This mold carrier is intermittently rotated or revolved through theco-actlon of an annular rack or rack ring 28 with a ratchet mechanism,and, as indicated in Figure l a stationary trimming knife or cutter 29is located adjacent the rotary mold for a purpose to be described. Thereare two of these knives or cutters employed, one at each side of therotary mold, for trimming the opposite ends of the briquette D.

In the initial operation of the briquette making machine, all of theseries of molds M are loaded with a dummy-brlquette, that is, a solid,cylindrical, wooden block of the same size and shape of the briquette tobe manufactured, is placed in each mold M.

The rotary mold carrier is turned, intermittently, to bring eachsucceeding block in a mold to the lowermost station of the carrier, andthus each block is successively brought into axial alinement with therotary compression head and the yielding-resistance compression'head. Asa successive core'C is lengthenedinto a hriquette D, the dummy-blocksare successively discharged from the carrier, until all of the blockshave been replaced by briquettes D. Then the lowermost briquette D initsmold M is clamped, between the forward end of the core C and theadjoining face of the reciprocating head 17 while the latter isinadvanced position. As the rotary compression head lays the spirallamination to form the core C and thereby increases the length of thecore, the latter gradually forces the briquette D, against the yieldingresistance of the head 1'1, from itsmold M, and the completed briquetteD, after having been moved to position free from the carrier, drops to awaiting receptacle, or is disposed of in other suitable manner.

When the core C has displaced the briquette D, the former occupies themold M and atthat time the rotary mold carrier is moved one step tobring a succeeding mold and briquette into alinement with the twocompression heads 13 and 1'7, and a succeeding briquette is fashioned. 4As the carrier revolves, it carries the briquettes in their moldssuccessively past the knives 29 which trim off the opposite ends of thebriquettes to insure a uniform length for the completed briquettes.

Thus it will be apparent that after the briquet-te has been fashioned inits mold M, the briquette remains therein during one complete revolutionof the carrier, before the briquette is removed from the mold. Duringthis revolution of the carrier the briquette is cooled, by thecirculation of water through the water jacket and in contact with.theenclosed mold, and at the time for delivery of the completed briquette,the

latter is properly cooled to insure its density and solidity.

It will be understood that the motor 5, and'' the other prime movers,employed to rotate the carrier and reciprocate the head 17,respectively, are all controlled, as by electrical devices, so that theintermittent movement of the rotary screw and its compression head; therotary movement of the mold carrier; and the reciprocating movement ofthe head 17, are produced at synchronized intervals, thus insuring thatthe operation of the machine is automatic, and the production ofsuccessive briquettes is accomplished with regularity and dispatch.

Apparatus other than the two-stage compression machine illustrated mightbe employed in pressing and feeding the material, the pressure of thesecond-stage, particularly, being of such high degree as to internallyheat the core by friction .and to express the moisture as oil, resin,

.pitch &c. to form an internal binder which permeates the entire coreand briquette to form a solid and dense block.

Thus it will be evident that a high degree of pressure is positivelyapplied to the rear end 0! the core C, and a yielding resistance orgradually receding pressure is applied to the outer end of the briquetteD. If a maximum density or solidity is desired for the completedbriquette, the hydraulic pressure back of the hydraulic piston isincreased to a maximum degree below the positive pressure on the core,and this hydraulic pressure is maintained in order that the briquettesmay be of uniform density.' If a less dense or solid briquette isdesired, the hydraulic pressure back of the hydraulic piston isdecreased in order that the reciprocating head may oppose the pressurefrom the rotary head with less resistance, but in such case the yieldingresistance is also uniform, in order that the density of the successivebriquettes may be uniform in character.

Thus the yielding resistance and consequent compression, whilesuflicient to overcome the re-' sistance or resiliency of the material,may be varied to suit diiferent kinds of wood employed in making thebriquettes; also to conform to the degree of moisture in the differentkinds of wood; and also to regulate the friction and consequent heatcreated or generated within the mass, the core, and the briquette, inthe formation of the self-binder.

Having thus fully described my invention, what I claim as new and desireto secure by Letters Patent is:

1. The continuous process of making a solid briquette from comminutedwoody material which consists in compressing and maintaining thematerial under pressure in a compact block, si-

briquettefrom comminuted woody material which' consists in compressingand maintaining the material under pressure in a compact block,simultaneously severing a continuous strip from one end of the block andlaying the strip in spiral laminations to form a core, simultaneouslyapplying pressure to the laminated core to form a solid, briquette, andinitiating cooling of the briquette while it is still under compression.

3. The continuous process of making a solid briquette from comminutedwoody material which consists in compressing and maintaining thematerial under pressure in a tubular compact block, simultaneouslysevering a continuous strip from one end of the block and laying thestrip in spiral laminations in a mold to form a core, and simultaneouslyapplying a greater degree of pressure to the laminated core to form thesolid briquette.

4. The continuous process of making a solid briquette from comminutedwoody material which consists in compressing and maintaining thematerial under pressure in a tubular compact block, simultaneouslyseparating a continuous strip from one end of the block and laying thestrip in spiral laminations in a mold to form a core, and simultaneouslyapplying pressure to one end of the core and a yielding resistance tothe other end of the core to form the solid briquette.

5. The continuous process of forming a solid cylindrical briquette fromcomminuted woody -material in its natural state under a pressurepressure.

ROBERT BOWLING.

